1. Field of the Invention
The present invention relates to an intaglio printing press, and especially, one useful when applied to printing of banknotes or securities.
2. Description of the Related Art
FIG. 2 shows an example of a conventional intaglio printing press applied to printing of banknotes or securities (see, for example, Japanese Unexamined Patent Publication No. 3-38347). As shown in FIG. 2, a so-called triple-size impression cylinder 112 is contacted with a transfer cylinder 111 disposed on a feed side of a sheet feeder 110, the triple-size impression cylinder 112 having three grippers disposed with equal spacing along a circumferential direction of the impression cylinder 112 so that three rubber blankets can be mounted. To the impression cylinder 112, a so-called triple-size plate cylinder 113 is opposed in contact therewith which can have three intaglio plates mounted along a circumferential direction of the plate cylinder 113. To the plate cylinder 113, a so-called triple-size ink collecting cylinder 114 is opposed in contact therewith which can have three rubber blankets mounted along a circumferential direction of the ink collecting cylinder 114. To the ink collecting cylinder 114, four chablon rollers (so-called single cylinders) 115 are opposed in contact therewith along a circumferential direction thereof. Each of the chablon rollers 115 has a circumferential surface length corresponding to the length of the blanket of the impression cylinder 112, or the length of the intaglio plate of the plate cylinder 113. To these chablon rollers 115, inking devices 116 for supplying ink are opposed in contact therewith. In these inking devices 116, inks of different colors are filled. Opposite and in contact with the plate cylinder 113 and downstream from the ink collecting cylinder 114, a wiping roller 117 is disposed for removing surplus ink adhering to the surface of the intaglio plate. The wiping roller 117 is immersed in a solvent stored in a wiping tank 118. To the impression cylinder 112, a delivery cylinder 119 of a delivery device 120 is opposed in contact therewith.
The foregoing conventional intaglio printing press is operated in the following manner:
When ink is supplied from each inking device 116 to each chablon roller 115, the ink is fed from the chablon roller 115 to the intaglio plates of the plate cylinder 113 via the blankets of the ink collecting cylinder 114. Surplus ink that has adhered to the surface of the intaglio plate is removed by the wiping roller 117. When a sheet is received from the transfer cylinder 111 of the sheet feeder 110 to the impression cylinder 112, the ink on the intaglio plate of the plate cylinder 113 is transferred to the sheet to perform printing. The printed sheet is passed on to the delivery cylinder 119, and discharged by the delivery device 120.
An intaglio printing press for printing of banknotes or securities is strongly required to have a further multicolor printing function (for printing in five or more colors), from the point of view of forgery prevention or the like. With the above-described conventional intaglio printing press, however, only up to four of the chablon rollers 115 and four of the inking devices 116 can be disposed around the ink collecting cylinder 114 because of the structure of the printing press. Thus, printing in five or more colors has been impossible.